Resin compositions for polymer solid electrolytes as well as polymer solid electrolytes and polymer batteries using them

ABSTRACT

Polymer solid electrolytes with good film strength, high ionic conductivity and excellent processability are provided, comprising a resin composition for polymer solid electrolytes containing 0.5–5.0% by weight of a curable resin having a specific structure (A), a plasticizer and (B) an electrolyte (C).

TECHNICAL FIELD

The present invention relates to resin compositions for polymer solidelectrolytes comprising 0.5–5.0% by weight of a curable resin (A), aplasticizer (B) and an electrolyte (C), as well as polymer solidelectrolytes and polymer batteries using them.

BACKGROUND ART

Conventional electrolytes used in electrochemical devices such asbatteries, capacitors and sensors are in the form of solutions or pastesto ensure ionic conductivity, but they are associated with problems suchas potential damage to the devices by leakage and the necessity of aseparator for immersing the electrolytes, which limits downsizing tosmaller and thinner devices. In contrast, products using solidelectrolytes are free from such problems and can be easily made thinner.Moreover, solid electrolytes are excellent in heat resistance andadvantageous for preparation processes of batteries or the like.

Especially, batteries using polymer-based solid electrolytes have theadvantage that they are more flexible than those based on inorganicmaterials so that they can be processed into various shapes. However,polymer solid electrodes so far proposed still have a problem of thesmall output current due to the low ionic conductivity. For example,proposed methods involve incorporating a specific alkali metal salt intoa mixture of an epichlorohydrin-based rubber and a low molecular weightpolyethylene glycol derivative to provide a polymer solid electrode (JPAHEI 2-235957) or crosslinking polyethylene glycol diacrylate bypolymerization reaction (JPA SHO 62-285954), but these electrolytes areinsufficient in film strength and need a support so that furtherimprovements would be desired in the balance of film strength, ionicconductivity, adhesion to electrodes, etc.

Recently, electric double layer capacitors comprising an ionicallyconductive solution inserted between polarizable electrodes made fromcarbon materials having a large specific surface area such as activatedcarbon or carbon black are often used in memory backup power sources orthe like. For example, JPA SHO 63-244570 discloses a capacitor usingRb₂Cu₃I₃Cl₇ with high electric conductivity as an inorganic-based solidelectrolyte. “Functional Materials” February, 1989, page 33 describes acapacitor using carbon-based polarizable electrodes and an organicelectrolyte. However, electric double layer capacitors using currentelectrolyte solutions have problems with long-term use and reliabilitybecause they are liable to leakage to the outside of the capacitors orother troubles during long-term use or abnormalities such as exposure tohigh voltage. Another problem of conventional inorganic-based ionicallyconductive materials lies in the low output voltage because of the lowelectrolytic voltage.

Polymer solid electrolyte layers in batteries and capacitors serve foronly ion migration, so that the batteries and capacitors can be providedwith smaller overall volume and higher energy density as the electrolytelayers become thinner. Batteries and capacitors using thin polymer solidelectrode layers can be provided with lower electric resistance andhigher output current and charging current, thereby improving the powerdensity of the batteries. Moreover, the cycle life can be improvedbecause corrosion by ions, especially alkali metal ions are less liableto occur. Thus, there have been demands for polymer solid electrolyteshaving a high ionic conductivity and a film strength as good as possibleso that they can be formed into thin films. In addition, they shouldhave a sufficient ion conductivity at low temperatures, taking intoaccount uses in low-temperature environments such as −10° C. or less.

DISCLOSURE OF THE INVENTION

The present invention aims to provide a resin composition for polymersolid electrolytes having a strength enough to eliminate the necessityof a support even if it is formed into a thin film of about several tensof μm and also having a high ionic conductivity at room temperature andlow temperatures and excellent processability.

As a result of careful studies to solve the problems described above, wefound that our object can be achieved by using a composition comprising0.5–5.0% by weight of a curable resin having a specific structure (A), aplasticizer and (B) an electrolyte (C). We further found that theproblems described above such as ion conductivity at room temperatureand low temperatures, film strength and processability are improved byusing a polymer solid electrolyte obtained by curing said composition ina battery, and finally accomplished the present invention.

Accordingly, the present invention relates to:

(1) a resin composition for polymer solid electrolytes comprising0.5–5.0% by weight of a curable resin(A), a plasticizer (B) and anelectrolyte (C);

(2) a resin composition for polymer solid electrolytes comprising0.5–3.0% by weight of a curable resin (A), a plasticizer (B) and anelectrolyte (C);

(3) the resin composition for polymer solid electrolytes as defined in(1) or (2) above wherein the curable resin (A) is a curable monomer(A-1) having four or more reactive functional groups in one molecule anda reactive functional group equivalent weight of 150 or less;

(4) the resin composition for polymer solid electrolytes as defined in(1) or (2) above wherein the curable resin (A) is a curable monomer(A-1) having four or more reactive functional groups in one molecule anda reactive functional group equivalent weight of 100 or less;

(5) the resin composition for polymer solid electrolytes as defined in(3) or (4) above wherein the reactive functional groups in the curablemonomer (A-1) are (meth)acrylate groups;

(6) the resin composition for polymer solid electrolytes as defined inany one of (3) to (5) above wherein the curable monomer (A-1) is a(meth)acrylate obtained by reacting 1 mol of a polyhydric alcohol with1–5 mol of caprolactone;

(7) the resin composition for polymer solid electrolytes as defined inany one of (3) to (6) above wherein the curable monomer (A-1) is one ormore members selected from the group consisting of caprolactone-modifiedtetra(meth)acrylates of pentaerythritol, caprolactone-modifiedtetra(meth)acrylates of ditrimethylolpropane, caprolactone-modifiedpenta(meth)acrylates of dipentaerythritol and caprolactone-modifiedhexa(meth)acrylates of dipentaerythritol;

(8) the resin composition for polymer solid electrolytes as defined in(1) or (2) above wherein the curable resin (A) is a curable polymer(A-2) having an ether bond in the backbone and an ethylenicallyunsaturated double bond in the side chain wherein the ethylenicallyunsaturated double bond has an equivalent weight of 300 or less;

(9) the resin composition for polymer solid electrolytes as defined in(8) above wherein the curable polymer (A-2) is a polymer obtained byreacting a compound (A-2-1) having one or more hydroxyl groups in onemolecule and a compound (A-2-2) having one ethylenically unsaturateddouble bond and one epoxy group in one molecule via the hydroxyl groupsand epoxy groups;

(10) the resin composition for polymer solid electrolytes as defined in(1) or (2) above wherein the curable resin (A) is a curable polymer(A-3) having an aliphatic chain containing 6 or less carbon atoms and anethylenically unsaturated double bond in the side chain wherein theethylenically unsaturated double bond has an equivalent weight of 850 orless;

(11) the resin composition for polymer solid electrolytes as defined inany one of (1) to (10) above further containing a photoinitiator (D);

(12) the resin composition for polymer solid electrolytes as defined in(11) above wherein the photoinitiator (D) has a maximum molar extinctioncoefficient of 50 or more at a wavelength of 350–450 nm;

(13) the resin composition for polymer solid electrolytes as defined inany one of (1) to (10) above further containing a thermal polymerizationinitiator (E);

(14) the resin composition for polymer solid electrolytes as defined in(13) above wherein the thermal polymerization initiator (E) has ahalf-life of 10 hours at a temperature of 10° C. or more;

(15) the resin composition for polymer solid electrolytes as defined inany one of (1) to (14) above wherein the electrolyte (C) is at least onemember selected from the group consisting of alkali metal salts,quaternary ammonium salts, quaternary phosphonium salts or transitionmetal salts;

(16) a polymer solid electrolyte comprising a cured product of the resincomposition for polymer solid electrolytes as defined in any one of (1)to (15) above;

(17) the polymer solid electrolyte as defined in (16) above in the formof a sheet; and

(18) a polymer battery comprising the polymer solid electrolyte asdefined in (16) or (17) above.

THE MOST PREFERRED EMBODIMENTS OF THE INVENTION

Resin compositions for polymer solid electrolytes of the presentinvention comprise 0.5–5.0% by weight of a curable resin having aspecific structure (A), a plasticizer (B) and an electrolyte (C),wherein the curable resin (A) is preferably a curable monomer (A-1) or acurable polymer (A-2) or (A-3).

In resin compositions for polymer solid electrolytes used in the presentinvention, a curable resin (A) having known reactive functional groupscan be used, where said reactive functional groups include(meth)acrylate, vinyl, epoxy, hydroxyl, carboxyl and isocyanate groups,especially (meth)acrylate. The curable resin (A) is preferably used in aratio of 0.5–5.0% by weight, especially 0.5–3.0% by weight to the totalresin composition. If the amount is 5.0% by weight or more, filmstrength is good but ion conductivity at room temperature and lowtemperatures decreases. If it is 0.5% by weight or less, however,sufficient film strength cannot be obtained.

When a curable monomer (A-1) is used as the curable resin in the presentinvention, the curable monomer (A-1) preferably has four or morereactive functional groups in one molecule and a reactive functionalgroup equivalent weight of 150 or less in order to provide sufficientfilm strength even at a resin concentration of 5.0% by weight or less,such as ditrimethylolpropane tetra(meth)acrylate, ethyleneoxide-modified pentaerythritol tetra(meth)acrylate, propyleneoxide-modified pentaerythritol tetra(meth)acrylate, etc. Morepreferably, the curable monomer (A-1) has a reactive functional groupequivalent weight of 100 or less, such as pentaerythritol tetraacrylate,dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, etc.

The curable monomer (A-1) used in the present invention is preferably a(meth)acrylate obtained by reacting 1 mol of a polyhydric alcohol with1–5 mol of caprolactone. The polyhydric alcohol is preferably atetrafunctional or higher polyhydric alcohol, such as pentaerythritol,ditrimethylolpropane, dipentaerythritol, etc. The reaction product ofthe polyhydric alcohol and caprolactone can be obtained by reacting 1mol of a polyhydric alcohol with 1–5 mol of caprolactone as described inJPB HEI 1-58176 (Japanese Patent No. 1571324), for example. Specificexamples include caprolactone-modified tetra(meth)acrylates ofpentaerythritol, caprolactone-modified tetra(meth)acrylates ofditrimethylolpropane and caprolactone-modified dipentaerythritol pentaor hexa(meth)acrylates. The caprolactone used as a starting material is,e.g. γ-, δ- or ε-caprolactone, preferably ε-caprolactone.

The curable resin (A) may also be preferably a polymer (A-2) having anether bond in the backbone and an ethylenically unsaturated double bondin the side chain wherein the ethylenically unsaturated bond has anequivalent weight of 300 or less. The curable polymer (A-2) preferablyhas a molecular weight of 500–1,000,000, more preferably 1,000–500,000.

The curable polymer (A-2) used in the present invention is preferably apolymer obtained by reacting a compound (A-2-1) having one or morehydroxyl groups in one molecule and a compound (A-2-2) having oneethylenically unsaturated double bond and one epoxy group in onemolecule via the hydroxyl groups and epoxy groups.

The compound (A-2-1) having one or more hydroxyl groups in one moleculeused in the present invention includes monofunctional alcohols such asmethanol, ethanol, propanol, butanol, hexanol, methoxyethylene glycol,methoxypolyethylene glycol and methoxypolypropylene glycol; difunctionalalcohols such as ethylene glycol, diethylene glycol, polyethyleneglycol, propylene glycol, dipropylene glycol, polypropylene glycol,neopentyl glycol, 1,6-hexanediol, bisphenol A and ethoxy bisphenol A;polyfunctional alcohols such as trimethylolpropane, ethoxylatedtrimethylolpropane, propoxylated triethylene glycol, glycerin,ethoxylated glycerin, propoxylated glycerin, pentaerythritol,ethoxylated pentaerythritol, propoxylated pentaerythritol,dipentaerythritol, ethoxylated dipentaerythritol and propoxylateddipentaerythritol; and phenols such as phenol novolak and cresolnovolak.

The compound (A-2-2) having one ethylenically unsaturated double bondand one epoxy group in one molecule used in the present inventionincludes glycidyl (meth)acrylate, (meth)acryloyl methylcyclohexene oxideand vinylcyclohexene oxide, for example.

The compound (A-2-1) having one or more hydroxyl groups in one moleculeis preferably reacted with the compound (A-2-2) having one ethylenicallyunsaturated double bond and one epoxy group in one molecule in a molarratio of 1:1–100,000, especially 1:10–50,000. The molecular weight ofthe curable polymer (A-2) can be controlled by the ratio between thecompound (A-2-1) and the compound (A-2-2).

During the reaction, catalysts can be used. The catalysts includeorganic bases such as amines (e.g. methylamine, ethylamine, propylamineand piperazine), pyridines and imidazoles; organic acids such as formicacid, acetic acid and propionic acid; inorganic acids such as sulfuricacid and hydrochloric acid; alkyl metal alcoholates such as sodiummethylate; alkalis such as KOH and NaOH; Lewis acids such as BF₃, ZnCl₂,AlCl₃ and SnCl₄ or complexes thereof; and organic metal compounds suchas triethyl aluminium and zinc diethyl. These catalysts are preferablyused at 0.01%–10%, especially 0.1%–5% on the basis of the reactants.

The reaction temperature depends on the activity of the catalysts used,but preferably ranges from −50° C. to 200° C., especially −30° C. to100° C. The reaction period is preferably 30 minutes to 48 hours,especially 1 to 24 hours. During the reaction, polymerization inhibitorssuch as hydroquinone, methylhydroquinone, methoxyphenol andphenothiazine can be added.

During the reaction, solvents can be used. The solvents are notspecifically limited so far as they have no active hydrogen, and includeketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone;aromatics such as benzene, toluene and xylene; and ethers, aliphatichydrocarbons and esters.

The curable resin (A) may also be preferably a curable polymer (A-3)having an aliphatic chain containing 6 or less carbon atoms and anethylenically unsaturated double bond in the side chain wherein theethylenically unsaturated double bond has an equivalent weight of 850 orless. The curable polymer (A-3) is obtained by first preparing acopolymer of a compound having an aliphatic chain containing 6 or lesscarbon atoms and an ethylenically unsaturated double bond and the abovecompound (A-2-2) and then reacting it with a compound having oneunsaturated double bond and one carboxyl group each in one molecule. Thecurable polymer (A-3) preferably has a molecular weight of about1,000–1,000,000, more preferably 2,000–500,000.

The copolymer of a compound having an aliphatic chain containing 6 orless carbon atoms and an ethylenically unsaturated double bond and theabove compound (A-2-2) is obtained by copolymerizing a compound havingan aliphatic chain containing 6 or less carbon atoms and anethylenically unsaturated double bond such as methyl (meth)acrylate,ethyl (meth)acrylate, propyl (meth)acrylate, i-propyl (meth)acrylate,butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate andhexyl (meth)acrylate with the above compound (A-2-2). One or more ofthese compounds may be copolymerized or one or more ethylenicallyunsaturated monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl(meth)acrylate, (meth)acrylic acid, styrene, phenoxyethyl(meth)acrylate, benzyl (meth)acrylate and α-methyl styrene may becopolymerized. The above compound (A-2-2) is preferably used at 0.1–90%by weight, especially 1–50% by weight on the basis of the total amountof the unsaturated monomers used for preparing the copolymer (A-3).

These polymers are obtained by known polymerization techniques such assolution polymerization or emulsion polymerization. Taking solutionpolymerization as an example, an ethylenically unsaturated monomermixture is stirred with a polymerization initiator in a suitable organicsolvent with heating at preferably 50–100° C. under a nitrogen stream.Suitable organic solvents include alcohols such as ethanol, propanol,isopropanol, butanol, isobutanol, 2-butanol, hexanol and ethyleneglycol; ketones such as methyl ethyl ketone and cyclohexanone; aromatichydrocarbons such as toluene and xylene; cellosolves such as Cellosolveand butyl cellosolve; carbitols such as Carbitol and butyl carbitol;propylene glycol alkyl ethers such as propylene glycol methyl ether;polypropylene glycol alkyl ethers such as dipropylene glycol methylether; acetic acid esters such as ethyl acetate, butyl acetate,cellosolve acetate and propylene glycol monomethyl acetate; lactic acidesters such as ethyl lactate and butyl lactate; dialkyl glycol ethers;and carbonates such as ethylene carbonate and propylene carbonate; Theseorganic solvents can be used alone or in combination.

Preferably, the polymerization initiator can be a peroxide such asbenzoyl peroxide or an azo compound such as azobisisobutyronitrile, andthe reaction temperature is 40–150° C. and the reaction period is 1–50hours.

Then, the copolymer is reacted with a compound having one unsaturateddouble bond and one carboxyl group each in one molecule (e.g.(meth)acrylic acid). Preferably, the compound having one unsaturateddouble bond and one carboxyl group each in one molecule is reacted in aratio of 0.8–1.1 equivalents to 1 equivalent of the epoxy group of thecopolymer. In order to promote the reaction, 0.1–1% of a basic compoundsuch as triphenylphosphine, triphenylstibine, triethylamine,triethanolamine, tetramethylammonium chloride or benzyltriethylammoniumchloride is added into the reaction solution as a reaction catalyst. Inorder to prevent polymerization during the reaction, 0.05–0.5% of apolymerization inhibitor (e.g. methoxyphenol, methylhydroquinone,hydroquinone, phenothiazine) is preferably added into the reactionsolution. The reaction temperature is normally 90–150° C., and thereaction period is 5–40 hours.

In the present invention, a plasticizer (B) is used. A low molecularweight compound is preferably added into compositions of the presentinvention as the plasticizer (B) because it further improves the ionicconductivity of polymer solid electrolytes obtained after curing. Theplasticizer (B) is preferably added in a ratio of 1,600–19,900 parts byweight, especially 2,800–19,900 parts by weight to 100 parts by weightof component (A). The ionic conductivity of the polymer solidelectrolytes increases with this amount, but the mechanical strength ofthe polymer solid electrolytes decreases if it is too excessive.

Suitable compounds as the plasticizer (B) have good compatibility forcomponent (A), a high dielectric constant, a boiling point of 70° C. ormore and a wide electrochemically stable range. Such plasticizers (B)include oligoethers such as triethylene glycol methyl ether andtetraethylene glycol dimethyl ether; carbonates such as ethylenecarbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate,vinylene carbonate and (meth)acryloyl carbonate; aromatic nitriles suchas benzonitrile and tolunitrile; and dimethyl formamide, dimethylsulfoxide, N-methyl pyrrolidone, sulfolane and phosphoric acid esters.Among them, oligoethers and carbonates are preferred, especiallycarbonates.

In the present invention, an electrolyte (C) is used. The proportion ofthe electrolyte in compositions of the present invention is preferably0.1–50% by weight, especially 1–30% by weight. The ion migration issignificantly inhibited if the electrolyte (C) is excessive while theabsolute amount of ions is insufficient and the ion conductivitydecreases if it is too little.

The electrolyte (C) used in the present invention is not specificallylimited, but may be any electrolyte containing ions desired to beelectric charge carriers and desirably having a large dissociationconstant in polymer solid electrolytes obtained after curing.Recommended examples are alkali metal salts, quaternary ammonium saltssuch as (CH₃)₄NBF₆, quaternary phosphonium salts such as (CH₃)₄PBF₆,transition metal salts such as AgClO₄, or protonic acids such ashydrochloric acid, perchloric acid and fluoroboric acid, among whichalkali metals, quaternary ammonium salts, quaternary phosphonium saltsor transition metal salts are preferred.

Those alkali metal salts include e.g. LiCF₃SO₃, LiPF₆, LiClO₄, LiL,LiBF₄, LiSCN, LiAsF₆, NaCF₃SO₃, NaPF₆, NaClO₄, NaI, NaBF₄, NaAsF₆,KCF₃SO₃, KPF₆ and KI.

In the present invention, a photoinitiator (D) can be used. Thephotoinitiator (D) may be any known photoinitiator preferably having amaximum molar extinction coefficient of 50 or more at a wavelength of350–450 nm. Resin compositions of the present invention are madeUV-curable by using this photoinitiator (D). The photoinitiator (D) ispreferably used in a ratio of 0.5–70 parts by weight, especially 1–30parts by weight to 100 parts by weight of component (A).

Siuitable photoinitiators (D) include e.g.2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1 (Irgacure 369from Ciba Specialty Chemicals), 2,4-diethylthioxanthone,2-isopropylthioxanthone, Michler's ketone,4,4′-bis(diethylamino)benzophenone, bisacylphosphine oxides, etc.Especially preferred are phosphorous compounds such as bisacylphosphineoxides. Examples of bisacylphosphine oxides includebis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, etc.

These photoinitiators (D) can be combined with other photoinitiatorssuch as 1-hydroxy-2-cyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, methylphenyl glyoxylate and 2,2-diethoxyacetophenone.

In the present invention a thermal polymerization initiator (E) can beused. The thermal polymerization initiator (E) can be any known thermalpolymerization initiator preferably having a half-life of 10 hours at atemperature of 10° C. or more. Resin compositions of the presentinvention are made thermosetting by using this thermal polymerizationinitiator (E). The thermal polymerization initiator (E) is preferablyused in a ratio of 0.5–70 parts by weight, especially 0.1–30 parts byweight to 100 parts by weight of component (A).

Specific examples of the thermal polymerization initiator (E) include:

organic peroxides, e.g. ketone peroxides such as methyl ethyl ketoneperoxide, methyl isobutyl ketone peroxide, methylcyclohexanone peroxideand cyclohexanone peroxide; hydroperoxides such as 2,4,4-trimethylpentylhydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxideand t-butyl hydroperoxide; diacyl peroxides such as isobutyryl peroxide,2,4-dichlorobenzoyl peroxide, o-chlorobenzoyl peroxide,bis-3,5,5-trimethylhexanoyl peroxide, lauroyl peroxide, benzoyl peroxideand p-chlorobenzoyl peroxide; dialkyl peroxides such as dicumylperoxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane,1,3-bis(t-butylperoxyisopropyl)benzene, di-t-butyl peroxide,2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 andtris-(t-butylperoxy)triazine; peroxyketals such as1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane,1,1-di-(t-butylperoxy)cyclohexane, 2,2-di-(t-butylperoxy)butane,4,4-di-(t-butylperoxy)valeric acid-n-butyl ester and2,2-bis(4,4-di-t-butylperoxy-cyclohexyl)propane; alkyl peresters such as2,4,4-trimethylpentyl peroxyneodecanoate, α-cumyl peroxyneodecanoate,t-butyl peroxynonadecanoate and t-butyl peroxypivalate; alkyl peresterssuch as 2,2,4-trimethylpentyl peroxy-2-ethylhexanoate, t-amylperoxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-butylperoxyisobutyrate, di-t-butyl peroxyhexahydroterephthalate, t-butylperoxy-3,3,5-trimethylhexanoate, t-butyl peroxyacetate, t-butylperoxybenzoate and di-t-butyl peroxytrimethyladipate; and percarbonatessuch as di-3-methoxy peroxydicarbonate, di-2-ethylhexylperoxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate,diisopropyl peroxydicarbonate, t-butyl peroxyisopropylcarbonate,1,6-bis(t-butylperoxycarbonyloxy) hexane and diethyleneglycol-bis(t-butyl peroxycarbonate); and

azo compounds such as 1,1′-azobis(cyclohexane-1-carbonitrile),2,2′-azobis(2-methyl-butyronitrile), 2,2′-azobisisobutyronitrile,2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide},2,2′-azobis[2-methyl-N-(2-hydroxyethyl) propionamide],2,2′-azobis(2-methylpropionamide) dehydrate, azodi-t-octane and2-cyano-2-propylazoformamide, which may be used alone or in combinationof two or more.

In the present invention, reactive monomers (F) and reactive oligomers(G) and the like other than the curable resin (A) may be combined.Preferably, these reactive monomer (F) and reactive oligomer (G) areused each in a ratio of 0–100 parts by weight to 100 parts by weight ofcomponent (A).

Reactive monomers (F) include e.g. carbitol (meth)acrylate, polyethyleneglycol di(meth)acrylate, neopentyl glycol hydroxypivalatedi(meth)acrylate, trimethylolpropane tri(meth)acrylate,trimethylolpropane polyoxyethyl tri(meth)acrylate, etc.

Reactive oligomers (G) include e.g. polyester poly(meth)acrylates,urethane (meth)acrylates, epoxy (meth)acrylates, etc.

Polyester poly(meth)acrylates include e.g. reaction products of apolyester polyol consisting of a polyhydric alcohol and a polybasic acidor an anhydrate thereof with (meth)acrylic acid. Polyhydric alcoholsinclude e.g. ethylene glycol, neopentyl glycol, polyethylene glycol,trimethylolpropane, etc. and polybasic acids include e.g. succinic acid,adipic acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalicacid, trimellitic acid, etc.

Urethane (meth)acrylates include e.g. reaction products of a polyol andan organic isocyanate and a monohydroxyl-containing (meth) acrylate.Polyols include e.g. polyethylene glycol, polypropylene glycol,polyester polyol, polycaprolactone polyol, polycarbonate polyol,polytetramethylene glycol, etc., and organic isocyanates include e.g.tolylene diisocyanate, isophorone diisocyanate, hexamethylenediisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethanediisocyanate, etc. Monohydroxyl-containing (meth)acrylates include e.g.2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate,polyethylene glycol mono(meth)acrylate, pentaerythritoltri(meth)acrylate, etc.

Epoxy (meth)acrylates include e.g. reaction products of an aliphaticpolyglycidyl ether and (meth)acrylic acid. Aliphatic polyglycidyl ethersinclude e.g. glycerin diglycidyl ether, polyethylene glycol diglycidylether, polypropylene glycol diglycidyl ether, etc.

Resin compositions for polymer solid electrolytes of the presentinvention can be obtained by homogeneously mixing the curable resin (A),plasticizer (B), electrolyte (C), photoinitiator (D) and/or thermalpolymerization initiator (E) described above optionally with thereactive monomers (F) and reactive oligomers (G) described above as wellas another polymer (H) and/or solvent (I). If the solvent (I) is used,it may be any solvent that does not inhibit polymerization, such astetrahydrofuran, toluene, etc.

Resin compositions for polymer solid electrolytes having the variousformulations as described above are characterized in that the curableresin (A) is contained in an amount of 0.5–5.0% by weight in thecompositions.

In the present invention, the polymer (H) that can be optionally usedincludes polyethylene glycol, polyacrylonitrile, polybutadiene,poly(meth)acrylic acid esters, polystyrene, polyphosphazenes,polysiloxane or polysilane, etc. These polymers (H) are preferably usedin a ratio of 0–100 parts by weight to 100 parts by weight of component(A).

Polymer solid electrolytes of the present invention comprise curedproducts of the resin compositions for polymer solid electrolytesdescribed above. The cured products can be obtained by polymerizing theresin compositions for polymer solid electrolytes described above byirradiation with electromagnetic waves (energy rays) such as UV rays(e.g. UV rays at 1–100,000 mJ/cm²) or heating at 20–200° C. topolymerize them. Especially, the resin compositions for polymer solidelectrolytes described above are preferably formed into sheets(coatings, films) or the like and then polymerized by irradiation withelectromagnetic waves such as electron rays or UV rays or heating toprepare sheet-like polymer products, which are highly advantageous forapplications because of the wider freedom of processability. Sheet-likepolymer solid electrolytes can be typically prepared by applying theresin compositions for polymer solid electrolytes described above on asupport using various coaters or the like such as roll coaters, dipcoaters and curtain coaters, and then curing the resin compositions byirradiation with electromagnetic waves such as UV rays or heating. Thesupport may be an aluminum-deposited PET film, for example. In order tocure the surface more reliably, another support may be subsequentlyapplied on the surface of the cured film of the resin compositions andfurther irradiated with electromagnetic waves such as UV rays or heated.Such another support may be a polypropylene film, for example. Thusobtained cured products are normally used after removing the support.

Polymer batteries of the present invention have a structure comprisingsuch a polymer solid electrolyte sandwiched between an anode and acathode, for example. The polymer batteries are preferably in the formof a sheet, so that the polymer solid electrolyte, anode and cathode arealso preferably in the form of a sheet.

The anode can be an anode active material processed into a sheetcombined with a binder resin used for bonding a collector such as analuminum, copper or nickel foil or the like and the anode activematerial. Preferred anode active materials for obtaining high-voltageand high-capacity batteries are low-redox potential materials havingalkali metal ions as carriers including alkali metals, alkali metalalloys such as lithium/aluminum alloys or lithium/lead alloys orlithium/antimony alloys and carbon materials and mixtures thereof.Carbon materials are especially preferred because they are charged withLi ions at a low redox potential and they are stable and safe. Carbonmaterials capable of charging and discharging Li ions include naturalgraphite, artificial graphite, graphite grown from gas-phase, petroleumcoke, coke, pitch-based carbons, polyacenes, fullerenes such as C₆₀ andC₇₀.

The cathode can be a cathode active material processed into a sheet witha binder resin used for bonding a collector such as an aluminum, copperor nickel foil or the like and the cathode active material. Preferredcathode active materials for obtaining high-voltage and high-capacitybatteries are high-redox potential materials such as metal oxides, metalsulfides, electrically conductive polymers or carbon materials ormixtures thereof. Especially, metal oxides such as cobalt oxide,manganese oxide, vanadium oxide, nickel oxide and molybdenum oxide andmetal sulfides such as molybdenum sulfide, titanium sulfide and vanadiumsulfide are preferably used to attain high packing density and thereforehigh volumetric energy density, while manganese oxide, nickel oxide,cobalt oxide and the like are preferred for high capacity and highvoltage. These cathode active materials are preferably used with Lielements inserted into (complexed with) metal oxides or metal sulfidesin the form of LiCoO₂ or LiMnO₂, for example. Cathodes can be preparedby inserting Li elements as descrobed above or by mixing a salt such asLi₂CO₃ and a metal oxide and heating the mixture as described in U.S.Pat. No. 4,357,215.

Electrically conductive polymers are also preferably used as cathodeactive materials because they are enough flexible to be easily formedinto thin films. Electrically conductive polymers include e.g.polyaniline, polyacetylene and derivatives thereof, polypyrrole andderivatives thereof, polythienylene and derivatives thereof,polypyridinediyl and derivatives thereof, polyisothianaphthenylene andderivatives thereof, polyfurylene and derivatives thereof,polyselenophene and derivatives thereof, and poly(arylene vinylenes)such as polyparaphenylene vinylene, polythienylene vinylene,polyfurylene vinylene, polynaphthenylene vinylene, polyselenophenevinylene, polypyridinediyl vinylene and derivatives thereof. Especiallypreferred are polymers of aniline derivatives soluble in organicsolvents.

In these batteries and electrodes, conductive polymers used as electrodeactive materials are prepared according to chemical or electrochemicalprocesses or other known processes.

EXAMPLES

The present invention is further illustrated by way of representativeexamples below. These examples are given only for illustrative purposes,but are not construed to limit the invention thereto.

Synthesis Example 1 Synthesis Example of Curable Polymer (A-2)

In a round-bottomed flask equipped with a stirrer and a condenser tube,100 g of ethylene glycol dimethyl ether as reaction medium, 15.0 g oftriethylene glycol as (A-2-1), 0.1 g of methoxyphenol and 0.1 g of BF₃etherate were added and heated to 50° C. Then, 85.2 g of glycidylmethacrylate as (A-2-2) was added dropwise with stirring over 2 hoursand reacted for 10 hours. A curable polymer solution having amethacrylate equivalent weight of 167, a solids content of 50% and aweight average molecular weight of 2,000 (by GPC) was obtained.

Synthesis Example 2 Synthesis Example of Curable Polymer (A-2)

In a round-bottomed flask equipped with a stirrer and a condenser tube,100 g of ethylene glycol dimethyl ether as reaction medium, 5.0 g oftriethylene glycol as (A-2-1), 0.1 g of methoxyphenol and 0.1 g of BF₃etherate were added and heated to 50° C. Then, 95.0 g of glycidylmethacrylate as (A-2-2) was added dropwise with stirring over 2 hoursand reacted for 10 hours. A polymer solution having a methacrylateequivalent weight of 149, a solids content of 50% and a weight averagemolecular weight of 6,000 (by GPC) was obtained.

Synthesis Example 3 Synthesis Example of Curable Polymer (A-2)

In a round-bottomed flask equipped with a stirrer and a condenser tube,100 g of ethylene glycol dimethyl ether as reaction medium, 6.7 g oftrimethylolpropane as (A-2-1), 0.1 g of methoxyphenol and 0.1 g of BF₃etherate were added and heated to 50° C. Then, 93.3 g of glycidylmethacrylate as (A-2-2) was added dropwise with stirring over 2 hoursand reacted for 10 hours. A polymer solution having a methacrylateequivalent weight of 151, a solids content of 50% and a weight averagemolecular weight of 4,000 (by GPC) was obtained.

Synthesis Example 4 Synthesis Example of Curable Polymer (A-2)

In a round-bottomed flask equipped with a stirrer and a condenser tube,100 g of ethylene glycol dimethyl ether as reaction medium, 3.4 g oftrimethylolpropane as (A-2-1), 0.1 g of methoxyphenol and 0.1 g of BF₃etherate were added and heated to 50° C. Then, 96.3 g of glycidylmethacrylate as (A-2-2) was added dropwise with stirring over 2 hoursand reacted for 10 hours. A polymer solution having a methacrylateequivalent weight of 146, a solids content of 50% and a weight averagemolecular weight of 8,000 (by GPC) was obtained.

Synthesis Example 5 Synthesis Example of Curable Polymer (A-3)

In a round-bottomed flask equipped with a stirrer and a condenser tube,105 g of i-butyl methacrylate, 45 g of glycidyl methacrylate, 150 g ofpropylene carbonate and 4.5 g of benzoyl peroxide were added and reactedat 75° C. for 5 hours under a nitrogen stream to give a polymer solutionhaving a solids content of 50% and a weight average molecular weight of20,000 (by GPC). To 300 g of this polymer solution were added 22.0 g ofacrylic acid, 0.16 g of methylhydroquinone, 0.9 g of triphenylphosphineand 22.0 g of propylene carbonate and mixed in solution and reacted at95° C. for 32 hours to give a polymer solution having an acrylateequivalent weight of 563, a solids content of 50% and a weight averagemolecular weight of 23,000 (by GPC).

Synthesis Example 6 Synthesis Example of Curable Polymer (A-3)

In a round-bottomed flask equipped with a stirrer and a condenser tube,65 g of i-butyl acrylate, 40 g of methyl acrylate, 45 g of glycidylmethacrylate, 150 g of propylene carbonate and 4.5 g of benzoyl peroxidewere added and reacted at 75° C. for 5 hours under a nitrogen stream togive a polymer solution having a solids content of 50% and a weightaverage molecular weight of 20,000 (by GPC). To 300 g of this polymersolution were added 22.0 g of acrylic acid, 0.16 g ofmethylhydroquinone, 0.9 g of triphenylphosphine and 22.0 g of propylenecarbonate and mixed in solution and reacted at 95° C. for 32 hours togive a polymer solution having an acrylate equivalent weight of 563, asolids content of 50% and a weight average molecular weight of 23,000(by GPC).

Synthesis Example 7 Synthesis Example of Curable Polymer (A-3)

In a round-bottomed flask equipped with a stirrer and a condenser tube,120 g of ethyl acrylate, 30 g of glycidyl methacrylate, 150 g ofpropylene carbonate and 4.5 g of benzoyl peroxide were added and reactedat 75° C. for 5 hours under a nitrogen stream to give a polymer solutionhaving a solids content of 50% and a weight average molecular weight of20,000 (by GPC). To 300 g of this polymer solution were added 15.0 g ofacrylic acid, 0.16 g of methylhydroquinone, 0.9 g of triphenylphosphineand 15.0 g of propylene carbonate and mixed in solution and reacted at95° C. for 32 hours to give a polymer solution having an acrylateequivalent weight of 792, a solids content of 50% and a weight averagemolecular weight of 23,000 (by GPC).

Example 1

A mixed electrolyte solution was obtained by thoroughly mixing 0.3 g ofcaprolactone-modified dipentaerythritol hexaacrylate (modified with 2mol ε-caprolactone) (functionality 6, acrylate equivalent weight=134;KAYARAD DPCA-20 (manufactured by Nippon Kayaku Co., Ltd.)) as curablemonomer (A-1), 4.85 g of ethylene carbonate and 4.85 g of diethylcarbonate as plasticizers (B), 1.0 g of LiPF₆ as electrolyte (C) and0.03 g of benzoyl peroxide (thermal polymerization initiator) as thermalpolymerization initiator (E) in an argon atmosphere. This mixed solutionwas applied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then covered with a propylene film (30 μm) and theassembly was heated at 80° C. for 5 hours, after which the top andbottom films were separated to give a polymer solid electrolyte in theform of a transparent self-supporting film having a thickness of about30 μm. This film was measured for ionic conductivity at 25° C. and −20°C. to show 3.0 ms/cm (25° C.) and 0.3 ms/cm (−20° C.).

Example 2

A mixed electrolyte solution was obtained by thoroughly mixing 0.4 g ofditrimethylolpropane tetraacrylate (functionality 4, acrylate equivalentweight=116; KAYARAD T-1420 (manufactured by Nippon Kayaku Co., Ltd.)) as(A-1), 4.8 g of ethylene carbonate and 4.8 g of diethyl carbonate as(B), 1.0 g of LiBF₄ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) in an argon atmosphere. This mixedsolution was applied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high voltage mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 4.2 ms/cm (25° C.) and 0.4 ms/cm (−20°C.).

Example 3

A mixed electrolyte solution was obtained by thoroughly mixing 0.2 g ofa mixture of dipentaerythritol hexaacrylate (functionality 6, acrylateequivalent weight=91) dipentaerythritol pentaacrylate (functionality 5,acrylate equivalent weight=105) (KAYARAD DPHA (manufactured by NipponKayaku Co., Ltd.)) as (A-1), 4.9 g of ethylene carbonate and 4.9 g ofdiethyl carbonate as (B), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) in an argon atmosphere. This mixedsolution was applied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film. (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.8 ms/cm (25° C.) and 0.4 ms/cm (−20°C.).

Example 4

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofthe curable polymer solution obtained in Synthesis example 1 as curablepolymer (A-2), 4.5 g of ethylene carbonate and 4.5 g of diethylcarbonate as (B), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) in an argon atmosphere. This mixedsolution was applied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.0 ms/cm (25° C.) and 0.3 ms/cm (−20°C.).

Example 5

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofthe polymer solution obtained in Synthesis example 2 as (A-2), 4.5 g ofethylene carbonate and 4.5 g of diethyl carbonate as (B), 1.0 g of LiPF₆as (C) and 0.03 g of benzoyl peroxide (thermal polymerization initiator)as (E) in an argon atmosphere. This mixed solution was applied in athickness of 30 μm on the aluminum layer of an aluminum-deposited PETfilm (30 μm) using a coater in an argon atmosphere and then covered witha propylene film (30 μm) and the assembly was heated at 80° C. for 5hours, after which the top and bottom films were separated to give apolymer solid electrolyte in the form of a transparent self-supportingfilm having a thickness of about 30 μm. This film was measured for ionicconductivity at 25° C. and −20° C. to show 2.5 ms/cm (25° C.) and 0.3ms/cm (−20° C.).

Example 6

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofthe polymer solution obtained in Synthesis example 3 as (A-2), 4.5 g ofethylene carbonate and 4.5 g of diethyl carbonate as (B), 1.0 g of LiPF₆as (C) and 0.03 g of benzoyl peroxide (thermal polymerization initiator)as (E) in an argon atmosphere. This mixed solution was applied in athickness of 30 μm on the aluminum layer of an aluminum-deposited PETfilm (30 μm) using a coater in an argon atmosphere and then covered witha propylene film (30 μm) and the assembly was heated at 80° C. for 5hours, after which the top and bottom films were separated to give apolymer solid electrolyte in the form of a transparent self-supportingfilm having a thickness of about 30 μm. This film was measured for ionicconductivity at 25° C. and −20° C. to show 3.0 ms/cm (25° C.) and 0.3ms/cm (−20° C.).

Example 7

A mixed electrolyte solution was obtained by thoroughly mixing 0.8 g ofthe polymer solution obtained in Synthesis example 4 as (A-2), 4.6 g ofethylene carbonate and 4.6 g of diethyl carbonate as (B), 1.0 g of LiPF₆as (C) and 0.03 g of benzoyl peroxide (thermal polymerization initiator)as (E) in an argon atmosphere. This mixed solution was applied in athickness of 30 μm on the aluminum layer of an aluminum-deposited PETfilm (30 μm) using a coater in an argon atmosphere and then covered witha propylene film (30 μm) and the assembly was heated at 80° C. for 5hours, after which the top and bottom films were separated to give apolymer solid electrolyte in the form of a transparent self-supportingfilm having a thickness of about 30 μm. This film was measured for ionicconductivity at 25° C. and −20° C. to show 3.0 ms/cm (25° C.) and 0.3ms/cm (−20° C.).

Example 8

A mixed electrolyte solution was obtained by thoroughly mixing 0.4 g ofditrimethylolpropane tetraacrylate (functionality 4, acrylate equivalentweight=116; KAYARAD T-1420 (manufactured by Nippon Kayaku Co., Ltd.)) as(A-1), 4.7 g of ethylene carbonate and 4.8 g of diethyl carbonate as(B), 1.0 g of LiBF₄ as (C), 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) and 0.1 g of trimethylolpropanetriacrylate as reactive monomer (F) in an argon atmosphere. This mixedsolution was applied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.8 ms/cm (25° C.) and 0.4 ms/cm (−20°C.).

Example 9

A mixed electrolyte solution was obtained by thoroughly mixing 0.4 g ofditrimethylolpropane tetraacrylate (functionality 4, acrylate equivalentweight=116; KAYARAD T-1420 (manufactured by Nippon Kayaku Co., Ltd.)) as(A-1), 4.7 g of ethylene carbonate and 4.7 g of diethyl carbonate as(B), 1.0 g of LiBF₄ as (C), 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) and 0.2 g of diacrylate ofpolyethylene glycol diglycidyl ether as reactive oligomers (G) in anargon atmosphere. This mixed solution was applied in a thickness of 30μm on the aluminum layer of an aluminum-deposited PET film (30 μm) usinga coater in an argon atmosphere and then irradiated with a high-pressuremercury lamp at 200 mJ/cm² to form a polymer solid electrolyte. Then, apropylene film (30 μm) was applied on this polymer solid electrolytelayer and further irradiated with a high-pressure mercury lamp at 300mJ/cm², after which the top and bottom films were separated to give apolymer solid electrolyte in the form of a transparent self-supportingfilm having a thickness of about 30 μm. This film was measured for ionicconductivity at 25° C. and −20° C. to show 3.6 ms/cm (25° C.) and 0.3ms/cm (−20° C.).

Example 10

A mixed electrolyte solution was obtained by thoroughly mixing 0.4 g ofditrimethylolpropane tetraacrylate (functionality 4, acrylate equivalentweight=116; KAYARAD T-1420 (manufactured by Nippon Kayaku Co., Ltd.)) as(A-1), 4.7 g of ethylene carbonate and 4.8 g of diethyl carbonate as(B), 1.0 g of LiBF₄ as (C), 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as photoinitiator (D) and 0.1 g of polyacrylonitrile asother polymer (H) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.9 ms/cm (25° C.) and 0.4 ms/cm (−20°C.).

Example 11

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofthe curable polymer solution obtained in Synthesis example 1 as curablepolymer (A-2), 3.9 g of ethylene carbonate and 4.0 g of diethylcarbonate as (B), 1.0 g of LiPF₆ as (C), 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as (D), 0.1 g of trimethylolpropane triacrylate asreactive monomer (F) and 1.0 g of tetrahydrofuran as solvent (I) in anargon atmosphere. This mixed solution was applied in a thickness of 30μm on the aluminum layer of an aluminum-deposited PET film (30 μm) usinga coater in an argon atmosphere and then irradiated with a high-pressuremercury lamp at 200 mJ/cm² to form a polymer solid electrolyte. Then, apropylene film (30 μm) was applied on this polymer solid electrolytelayer and further irradiated with a high-pressure mercury lamp at 300mJ/cm², after which the top and bottom films were separated to give apolymer solid electrolyte in the form of a transparent self-supportingfilm having a thickness of about 30 μm. This film was measured for ionicconductivity at 25° C. and −20° C. to show 3.0 ms/cm (25° C.) and 0.3ms/cm (−20° C.).

Example 12

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofthe polymer solution obtained in Synthesis example 5 as curable polymer(A-3), 4.5 g of ethylene carbonate and 4.5 g of diethyl carbonate as(B), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as (D) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.0 ms/cm (25° C.) and 0.3 ms/cm (−20°C.).

Example 13

A mixed electrolyte solution was obtained by thoroughly mixing 0.8 g ofthe polymer solution obtained in Synthesis example 6 as curable polymer(A-3), 4.6 g of ethylene carbonate and 4.6 g of diethyl carbonate as(B), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as (D) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.2 ms/cm (25° C.) and 0.3 ms/cm (−20°C.).

Example 14

A mixed electrolyte solution was obtained by thoroughly mixing 0.6 g ofthe polymer solution obtained in Synthesis example 5 as curable polymer(A-3), 4.7 g of ethylene carbonate and 4.7 g of diethyl carbonate as(B), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as (D) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 3.2 ms/cm (25° C.) and 0.3 ms/cm (−20°C.).

Comparative Example 1

A mixed electrolyte solution was obtained by thoroughly mixing 1.0 g ofcaprolactone-modified dipentaerythritol hexaacrylate (modified with 12mol ε-caprolactone) (functionality 6, acrylate equivalent weight=325;KAYARAD DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.)) in place ofcurable resin (A), 4.5 g of ethylene carbonate and 4.5 g of diethylcarbonate as (13), 1.0 g of LiPF₆ as (C) and 0.05 g ofbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (radicalphotoinitiator) as (D) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then irradiated with a high-pressure mercury lamp at 200mJ/cm² to form a polymer solid electrolyte. Then, a propylene film (30μm) was applied on this polymer solid electrolyte layer and furtherirradiated with a high-pressure mercury lamp at 300 mJ/cm², after whichthe top and bottom films were separated to give a polymer solidelectrolyte in the form of a transparent self-supporting film having athickness of about 30 μm. This film was measured for ionic conductivityat 25° C. and −20° C. to show 2.5 ms/cm (25° C.) and 0.2 ms/cm (−20°C.).

Comparative Example 2

A mixed electrolyte solution was obtained by thoroughly mixing 0.6 g ofethylene oxide-modified trimethylolpropane triacrylate (functionality 3,acrylate equivalent weight=142; KAYARAD THE-330 (manufactured by NipponKayaku Co., Ltd.)) in place of curable resin (A), 4.7 g of ethylenecarbonate and 4.7 g of diethyl carbonate as (B), 1.0 g of LiPF₆ as (C)and 0.03 g of benzoyl peroxide (thermal polymerization initiator) as (E)in an argon atmosphere. This mixed solution was applied in a thicknessof 30 μm on the aluminum layer of an aluminum-deposited PET film (30 μm)using a coater in an argon atmosphere and then heated at 80° C. for 5hours to give a polymer solid electrolyte in the form of a transparentself-supporting film having a thickness of about 30 μm. This film wasmeasured for ionic conductivity at 25° C. and −20° C. to show 3.0 ms/cm(25° C.) and 0.2 ms/cm (−20° C.).

Comparative Example 3

A mixed electrolyte solution was obtained by thoroughly mixing 0.3 g ofethylene oxide-modified trimethylolpropane triacrylate (functionality 3,acrylate equivalent weight=142) in place of curable resin (A), 4.85 g ofethylene carbonate and 4.85 g of diethyl carbonate as (13), 1.0 g ofLiPF₆ as (C) and 0.03 g of benzoyl peroxide (thermal polymerizationinitiator) as (E) in an argon atmosphere. This mixed solution wasapplied in a thickness of 30 μm on the aluminum layer of analuminum-deposited PET film (30 μm) using a coater in an argonatmosphere and then heated at 80° C. for 5 hours, but the mixed solutionwas not cured and any polymer solid electrode in the form of aself-supporting film could not be obtained.

It is shown from the results above that compositions are not cured at aresin concentration of 3% and require a high resin concentration forcuring them and the ionic conductivity at low temperatures decreaseswhen using curable monomers having a high functional group equivalentweight such as 325 despite the functionality of 6 as in Comparativeexample 1 or having a low functionality such as 3 despite the lowfunctional group equivalent weight as in Comparative examples 2 and 3.However, it is shown that polymer solid electrolytes obtained by curingresin compositions using curable monomer (A-1) of the present inventionare enough strong so that they can be separated from their support andthat they have good thin film strength and high ionic conductivity,especially excellent ionic conductivity at low temperatures. It is alsoshown that polymer solid electrolytes using curable polymers (A-2, A-3)are enough strong so that they can be separated from their support andthat they have good thin film strength and high ionic conductivity,especially excellent ionic conductivity at low temperatures even if thefunctional group equivalent weight is relatively high. This isattributed to the low resin concentration in the solid electrolytes.

INDUSTRIAL APPLICABILITY

Resin compositions for polymer solid electrolytes of the presentinvention comprising 0.5–5.0 by weight of a curable resin having aspecific structure (A), a plasticizer (B) and an electrolyte (C) areexcellent in thin film processability so that they are readily formedinto thin films with good film strength. Polymer solid electrolytesobtained by curing the resin compositions are characterized by good filmstrength and high ionic conductivity.

1. A resin composition for polymer solid electrolytes comprising0.5–5.0% by weight of a curable resin (A), a plasticizer (B) and anelectrolyte (C), the curable resin (A) being a curable monomer (A-1)which is a (meth)acrylate of a reaction product obtained by reacting 1mol of a polyhydric alcohol with 1–5 mol of caprolactone; a curablepolymer (A-2) which is a polymer obtained by reacting a compound (A-2-1)having one or more hydroxyl groups in one molecule and a compound(A-2-2) having one ethylenically unsaturated double bond and one epoxygroup in one molecule via the hydroxyl groups and epoxy groups whereinthe ethylenically unsaturated double bond has an equivalent weight of300 or less; or a curable polymer (A-3) which is a polymer obtained byfirst preparing a copolymer of a compound having both an aliphatic chaincontaining 6 or less carbon atoms and an ethylenically unsaturateddouble bond and the above compound (A-2-2) and then reacting it with acompound having one unsaturated double bond and one carboxyl group eachin one molecule.
 2. The resin composition for polymer solid electrolytesas defined in claim 1 wherein the curable monomer (A-1) is one or moremembers selected from the group consisting of caprolactone-modifiedtetra(meth)acrylates of pentaerythritol, caprolactone-modifiedtetra(meth)acrylates of ditrimethylolpropane, caprolactone-modifiedpenta(meth)acrylates of dipentaerythritol and caprolactone-modifiedhexa(meth)acrylates of dipentaerythritol.
 3. The resin composition forpolymer solid electrolytes as defined in claim 1 wherein theethylenically unsaturated double bond in the curable polymer (A-3) hasan equivalent weight of 850 or less.
 4. The resin composition forpolymer solid electrolytes as defined in claim 1 further containing aphotoinitiator (D).
 5. The resin composition for polymer solidelectrolytes as defined in claim 4 wherein the photoinitiator (D) has amaximum molar extinction coefficient of 50 or more at a wavelength of350–450 nm.
 6. The resin composition for polymer solid electrolytes asdefined in claim 1 further containing a thermal polymerization initiator(E).
 7. The resin composition for polymer solid electrolytes as definedin claim 6 wherein the thermal polymerization initiator (E) has ahalf-life of 10 hours at a temperature of 10° C. or more.
 8. The resincomposition for polymer solid electrolytes as defined in claim 1 whereinthe electrolyte (C) is at least one member selected from the groupconsisting of alkali metal salts, quatemary ammonium salts, quatemaryphosphonium salts and transition metal salts.
 9. A polymer solidelectrolyte comprising a cured product of the resin composition forpolymer solid electrolytes as defined in any one of claims 1, 2, 3, 4,5, 6, 7 or
 8. 10. The polymer solid electrolyte as defined in claim 9 inthe form of a sheet.
 11. A polymer battery comprising the polymer solidelectrolyte as defined in claim 10.